Process for preparing atazanavir bisulfate and novel forms

ABSTRACT

A process is provided for preparing the HIV protease inhibitor atazanavir bisulfate wherein a solution of atazanavir free base is reacted with concentrated sulfuric acid in an amount to react with less than about 15% by weight of the free base, seeds of Form A crystals of atazanavir bisulfate are added to the reaction mixture, and as crystals of the bisulfate form, additional concentrated sulfuric acid is added in multiple stages at increasing rates according to a cubic equation, to effect formation of Form A crystals of atazanavir bisulfate. A process is also provided for preparing atazanavir bisulfate as Pattern C material. A novel form of atazanavir bisulfate is also provided which is Form E3 which is a highly crystalline triethanolate solvate of the bisulfate salt from ethanol.

REFERENCE TO OTHER APPLICATIONS

The present application takes priority from U.S. provisional applicationNos. 60/568,043, filed May 4, 2004, and 60/607,533, filed Sep. 7, 2004,the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a process for preparing the HIVprotease inhibitor atazanavir bisulfate and novel forms thereof.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 5,849,911 to Fässler et al. discloses a series ofazapeptide HIV protease inhibitors (which includes atazanavir) whichhave the structure

wherein

-   -   R₁ is lower alkoxycarbonyl,    -   R₂ is secondary or tertiary lower alkyl or lower alkylthio-lower        alkyl,    -   R₃ is phenyl that is unsubstituted or substituted by one or more        lower alkoxy radicals, or C₄-C₈ cycloalkyl,    -   R₄ is phenyl or cyclohexyl each substituted in the 4-position by        unsaturated heterocyclyl that is bonded by way of a ring carbon        atom, has from 5 to 8 ring atoms, contains from 1 to 4 hetero        atoms selected from nitrogen, oxygen, sulfur, sulfinyl (—SO—)        and sulfonyl (—SO₂—) and is unsubstituted or substituted by        lower alkyl or by phenyl-lower alkyl,    -   R₅, independently of R₂, has one of the meanings mentioned for        R₂, and    -   R₆, independently of R₁, is lower alkoxycarbonyl, or a salt        thereof, provided that at least one salt-forming group is        present which includes various pharmaceutically acceptable acid        addition salts thereof.

Several methods for preparing the azapeptides are provided includingpreparation of a compound where R₁ and R₆, and R₂ and R₅ are in eachcase two identical radicals, wherein a diamino compound of the structure

is condensed with an acid of the structure

or with a reactive acid derivative thereof, wherein R₁ and R₂ are asdefined for R₁ and R₆, and for R₂ and R₅, respectively.

In forming atazanavir employing the above method the diamino compound(a) which will have the structure

is prepared by coupling the epoxide

with a hyrazinocarbamate

in the presence of isopropyl alcohol to form the protected diamine

which is treated with hydrochloric acid in the presence a solvent suchas tetrahydrofuran to form the diamine (a)

The diamine is isolated and used in the next coupling step where it isreacted with an acid (b)

or a reactive ester thereof employing a coupling agent such asO-(1,2-dihydro-2-oxo-1-pyridyl)-N,N,N¹,N¹-tetramethyluronium-tetrafluoro-borate(TPTU).

It has been found that the diamine free base is unstable and thereforeundesirable for use in preparing the free base of atazanavir.

U.S. Pat. No. 6,087,383 to Singh et al. discloses the bisulfate salt ofthe azapeptide HIV protease inhibitor known as atazanavir which has thestructure

(also referred to as atazanavir bisulfate or atazanavir sulfate).

Example 3 of Singh et al. describes the preparation of atazanavirbisulfate in the form of Type-II crystals which are a hydratedhygroscopic and crystalline form and Type-I crystals which appear to bean anhydrous/desolvated crystalline form.

BRIEF DESCRIPTION OF THE INVENTION

In accordance with the present invention, novel forms of atazanavirbisulfate are provided which includes Pattern C material and Form E3.Pattern C material is preferred.

In addition, in accordance with the present invention, a process isprovided for preparing atazanavir bisulfate in the form of Form Acrystals (bulk drug) (which are referred to as Type I crystals inExample 3 of U.S. Pat. No. 6,087,383 to Singh et al). The Form Acrystals prepared by the process of the invention have a desiredsubstantially consistent particle size distribution and substantiallyconsistent mean particle size, and are employed in the conversion toPattern C material, a partially crystalline material, which isformulated with various excipients to prepare the drug product.

The process of the invention for preparing Form A crystals of atazanavirbisulfate salt employs a modified cubic crystallization techniquewherein sulfuric acid is added at an increasing rate according to acubic equation (as described hereinafter), and includes the steps ofreacting a solution of atazanavir free base in an organic solvent (inwhich the atazanavir bisulfate salt is substantially insoluble) with afirst portion of concentrated sulfuric acid in an amount to react withless than about 15%, preferably less than about 12%, by weight of theatazanavir free base, adding seeds of atazanavir bisulfate Form Acrystals to the reaction mixture, and as crystals of atazanavirbisulfate form, adding additional concentrated sulfuric acid in multiplestages at increasing rates according to a cubic equation to effectformation of Form A crystals.

In addition, in accordance with the present invention, a process isprovided for preparing a form of atazanavir which is derived from andincludes atazanavir bisulfate, and which is referred to as Pattern Cmaterial. Pattern C may be produced by suspending crystals of Form A inwater and drying. Alternatively, Pattern C material may be formed bysubjecting crystals of Form A to high relative humidity of greater thanabout 95% RH (water vapor) for at least 24 hours. Pattern C material mayalso be formed by wet granulating the atazanavir bisulfate or acombination of atazanavir bisulfate and excipients and drying the wetgranulation.

In a preferred embodiment, Form A crystals are mixed with formulatingexcipients such as one or more bulking agents, for example lactose, oneor more disintegrants, such as crospovidone, and wet granulated todirectly form Pattern C material in admixture with the excipients.

Further in accordance with the present invention, a new form ofatazanavir bisulfate is provided, namely, Form E3 which is a highlycrystalline form of the triethanolate solvate of atazanavir bisulfate.

Form E3 is prepared by slurrying atazanavir free base in ethanol,treating the slurry with concentrated sulfuric acid, heating and seedingthe resulting solution with ethanol wet E3 crystals, treating themixture with heptane (or other solvent such as toluene or hexane),filtering and drying.

Still further in accordance with the present invention, a process isprovided for preparing Form A crystals of atazanavir bisulfate whichincludes the steps of preparing a triamine salt of the structure

(preferably the HCl (3 moles) salt) and without isolating the triaminesalt, reacting the triamine salt with an active ester, preferably of thestructure

in the presence of a base and organic solvent to form atazanavir freebase which, without isolating, is converted to the atazanavir bisulfatevia a modified cubic crystallization technique as described herein.

In addition, in accordance with the present invention, a novelatazanavir bisulfate composition is provided which includes atazanavirbisulfate as Form A crystals or Pattern C material, and apharmaceutically acceptable carrier therefor. The pharmaceuticallyacceptable carrier may include fillers, binders, disintegrants,lubricants, and other conventional excipients.

The various forms of atazanavir bisulfate according to the invention maybe characterized using various techniques, the operation of which arewell known to those of ordinary skill in the art. The forms may becharacterized and distinguished using single crystal X-ray diffraction,which is based on unit cell measurements of a single crystal of a format a fixed analytical temperature. A detailed description of unit cellsis provided in Stout & Jensen, X-Ray Structure Determination: APractical Guide, Macmillan Co., New York (1968), Chapter 3, which isherein incorporated by reference. Alternatively, the unique arrangementof atoms in spatial relation within the crystalline lattice may becharacterized according to the observed fractional atomic coordinates.Another means of characterizing the crystalline structure is by powderX-ray diffraction analysis in which the experimental or observeddiffraction profile is compared to a simulated profile representing purepowder material, both run at the same analytical temperature, andmeasurements for the subject form characterized as a series of 20values.

Other means of characterizing the form may be used, such as solid statenuclear magnetic resonance (SSNMR), differential scanning calorimetry(DSC) and thermal gravimetric analysis (TGA). These parameters may alsobe used in combination to characterize the subject form.

Form A crystals may be characterized by unit cell parameterssubstantially equal to the following:

Cell Dimensions:

-   -   a=9.86(5)Å    -   b=29.245(6)Å    -   c=8.327(2)Å    -   α=93.56(2)°    -   β=114.77(3)°    -   γ=80.49(3)°        Space Group 1        Molecules/Asymmetric Unit 2

-   wherein the crystalline form is at about +22° C.

Form A may be characterized by fractional atomic coordinatessubstantially as listed in Table 3 and the crystal structuresubstantially as shown in FIG. 2.

Form A may be characterized by simulated and observed powder X-raydiffraction patterns substantially as shown in FIG. 1.

Form A may be characterized by a differential scanning calorimetry (DSC)thermogram having an endotherm with peak onset at about 165.6° C.substantially as shown in FIG. 3.

Form A may be characterized by a thermal gravimetric analysis (TGA)curve having a negligible weight loss up to about 100° C. to 150° C.substantially as shown in FIG. 4.

Form A may be characterized by the solid-state NMR (SSNMR) chemicalshifts substantially as shown in Table 4 and by the spectrumsubstantially as shown in FIG. 5.

Form A may be characterized by fractional atomic coordinatessubstantially as listed in Table 5.

Form A salt may be characterized by moisture-sorption isotherms withabout 0.1% weight gain in the range from 25 to 75% RH at 25° C.

In one aspect of the present invention, Pattern C may be characterizedby the observed powder X-ray diffraction pattern substantially as shownin FIG. 5.

In a different aspect of the present invention, Pattern C may becharacterized by a differential scanning calorimetry thermogramsubstantially as shown in FIG. 7 having an endotherm typically in therange from about 76.7 to about 96.6° C. and from about 156.8 to about165.9° C.

In a different aspect of the present invention, Pattern C may becharacterized by a thermal gravimetric analysis curve having a weightloss of about 2.4% at about 125° C. and a weight loss of about 4.4% upto about 190° C. substantially as shown in FIG. 8.

In accordance with the present invention, Form E3 may be characterizedby crystallographic data as shown in Table 5, substantially equal to thefollowing:

-   -   a=10.749 Å    -   b=13.450(4)Å    -   c=9.250(2)Å    -   α=98.33(2)°    -   β=95.92(3)°    -   γ=102.82(3)°        Space Group P1        Molecules/Asymmetric Unit 1

-   when the crystalline form is at about −23° C.

In a different aspect of the present invention, Form E3 may becharacterized by fractional atomic coordinates substantially as listedin Table 6.

In a different aspect of the present invention, Form E3 may becharacterized by simulated and observed powder X-ray diffractionpatterns substantially as shown in FIG. 9.

In a different aspect of the present invention, Form E3 may becharacterized by a differential scanning calorimetry thermogram havingan endotherm typically within the range from about 89.4 to about 96.6°C. substantially as shown in FIG. 11.

In a different aspect of the present invention, Form E3 may becharacterized by a thermal gravimetric analysis curve having a weightloss of about 14.7% at about 150° C. substantially as shown in Table 8.

In a different aspect of the invention, Form E3 may be characterized bythe crystal structure substantially as shown in FIG. 10.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows calculated (simulated) (22° C.) and observed (experimentalat room temperature) powder X-ray diffraction patterns (CuKα λ=1.5418 Å)of Form A;

FIG. 2 shows the crystal structure of Form A;

FIG. 3 shows a differential scanning calorimetry (DSC) thermogram ofForm A;

FIG. 4 shows a thermal gravimetric analysis curve (TGA) of Form A;

FIG. 5 shows a C-13 solid state NMR of Form A;

FIG. 6 shows an observed (experimental at room temperature) powder X-raydiffraction pattern (CuKα λ=1.5418 Å) of Pattern C;

FIG. 7 shows a differential scanning calorimetry thermogram of PatternC;

FIG. 8 shows a thermal gravimetric analysis curve of Pattern C;

FIG. 9 shows calculated (simulated) (22° C.) and observed (experimentalat room temperature) powder X-ray diffraction patterns (CuKα λ=1.5418 Å)of Form E3;

FIG. 10 shows the crystal structure of Form E3; and

FIG. 11 shows a differential scanning calorimetry (DSC) thermogram ofForm E3, and a thermal gravimetric analysis curve of Form E3.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides, at least in part, forms of atazanavirbisulfate, namely, Form E3 and Pattern C, as novel materials, inparticular in pharmaceutically acceptable form. The term“pharmaceutically acceptable”, as used herein, refers to thosecompounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for contact withthe tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem complicationscommensurate with a reasonable benefit/risk ratio. In certain preferredembodiments, crystalline forms of free base I and salts thereof are insubstantially pure form. The term “substantially pure”, as used herein,means a compound having a purity greater than about 90% including, forexample, about 91%, about 92%, about 93%, about 94%, about 95%, about96%, about 97%, about 98%, about 99%, and about 100%.

As used herein “polymorph” refers to crystalline forms having the samechemical composition but different spatial arrangements of themolecules, atoms, and/or ions forming the crystal.

As used herein “solvate” refers to a crystalline form of a molecule,atom, and/or ions that further contains molecules of a solvent orsolvents incorporated into the crystalline structure. The solventmolecules in the solvate may be present in a regular arrangement and/ora non-ordered arrangement. The solvate may contain either astoichiometric or nonstoichiometric amount of the solvent molecules. Forexample, a solvate with a nonstoichiometric amount of solvent moleculesmay result from partial loss of solvent from the solvate.

Samples of the crystalline forms may be provided with substantially purephase homogeneity, indicating the presence of a dominant amount of asingle crystalline form and optionally minor amounts of one or moreother crystalline forms. The presence of more than one crystalline formin a sample may be determined by techniques such as powder X-raydiffraction (PXRD) or solid state nuclear magnetic resonancespectroscopy (SSNMR). For example, the presence of extra peaks in thecomparison of an experimentally measured PXRD pattern with a simulatedPXRD pattern may indicate more than one crystalline form in the sample.The simulated PXRD may be calculated from single crystal X-ray data. seeSmith, D. K., “A FORTRAN Program for Calculating X-Ray PowderDiffraction Patterns,” Lawrence Radiation Laboratory, Livermore, Calif.,UCRL-7196 (April 1963). Preferably, the crystalline form hassubstantially pure phase homogeneity as indicated by less than 10%,preferably less than 5%, and more preferably less than 2% of the totalpeak area in the experimentally measured PXRD pattern arising from theextra peaks that are absent from the simulated PXRD pattern. Mostpreferred is a crystalline form having substantially pure phasehomogeneity with less than 1% of the total peak area in theexperimentally measured PXRD pattern arising from the extra peaks thatare absent from the simulated PXRD pattern.

Procedures for the preparation of crystalline forms are known in theart. The crystalline forms may be prepared by a variety of methods,including for example, crystallization or recrystallization from asuitable solvent, sublimation, growth from a melt, solid statetransformation from another phase, crystallization from a supercriticalfluid, and jet spraying. Techniques for crystallization orrecrystallization of crystalline forms from a solvent mixture include,for example, evaporation of the solvent, decreasing the temperature ofthe solvent mixture, crystal seeding a supersaturated solvent mixture ofthe molecule and/or salt, freeze drying the solvent mixture, andaddition of antisolvents (countersolvents) to the solvent mixture.

Crystals of drugs, including polymorphs, methods of preparation, andcharacterization of drug crystals are discussed in Solid-State Chemistryof Drugs, S. R. Byrn, R. R. Pfeiffer, and J. G. Stowell, 2^(nd) Edition,SSCI, West Lafayette, Ind. (1999).

For crystallization techniques that employ solvent, the choice ofsolvent or solvents is typically dependent upon one or more factors,such as solubility of the compound, crystallization technique, and vaporpressure of the solvent. Combinations of solvents may be employed, forexample, the compound may be solubilized into a first solvent to afforda solution, followed by the addition of an antisolvent to decrease thesolubility of the compound in the solution and to afford the formationof crystals. An antisolvent is a solvent in which the compound has lowsolubility. Suitable solvents for preparing crystals include polar andnonpolar solvents.

In one method to prepare crystals, atazanavir bisulfate is suspendedand/or stirred in a suitable solvent to afford a slurry, which may beheated to promote dissolution. The term “slurry”, as used herein, meansa saturated solution of atazanavir bisulfate or a salt thereof, whichmay also contain an additional amount of atazanavir bisulfate or saltthereof to afford a heterogeneous mixture of atazanavir bisulfate orsalt thereof and a solvent at a given temperature. Suitable solvents inthis regard include, for example, polar aprotic solvents, and polarprotic solvents, and mixtures of two or more of these as disclosedherein.

Seed crystals may be added to any crystallization mixture to promotecrystallization. As will be clear to the skilled artisan, seeding isused as a means of controlling growth of a particular crystalline formor as a means of controlling the particle size distribution of thecrystalline product. Accordingly, calculation of the amount of seedsneeded depends on the size of the seed available and the desired size ofan average product particle as described, for example, in “Programmedcooling of batch crystallizers,” J. W. Mullin and J. Nyvlt, ChemicalEngineering Science (1971) 26:369-377. In general, seeds of small sizeare needed to effectively control the growth of crystals in the batch.Seeds of small size may be generated by sieving, milling, or micronizingof larger crystals, or by micro-crystallization of solutions. Careshould be taken that milling or micronizing of crystals does not resultin any change in crystallinity from the desired crystal form (i.e.change to amorphous or to another polymorph).

A cooled mixture may be filtered under vacuum, and the isolated solidsmay be washed with a suitable solvent, such as cold recrystallizationsolvent, and dried under a nitrogen purge to afford the desiredcrystalline form. The isolated solids may be analyzed by a suitablespectroscopic or analytical technique, such as SSNMR, DSC, PXRD, or thelike, to assure formation of the preferred crystalline form of theproduct. The resulting crystalline form is typically produced in anamount of greater than about 70 weight % isolated yield, but preferablygreater than 90 weight % based on the weight of atazanavir bisulfateoriginally employed in the crystallization procedure. The product may becomilled or passed through a mesh screen to delump the product, ifnecessary.

Crystalline forms may be prepared directly from the reaction medium ofthe final process step for preparing atazanavir bisulfate. This may beachieved, for example, by employing in the final process step a solventor mixture of solvents from which atazanavir bisulfate may becrystallized. Alternatively, crystalline forms may be obtained bydistillation or solvent addition techniques. Suitable solvents for thispurpose include any of those solvents described herein, including proticpolar solvents such as alcohols, and aprotic polar solvents such asketones.

By way of general guidance, the reaction mixture may be filtered toremove any undesired impurities, inorganic salts, and the like, followedby washing with reaction or crystallization solvent. The resultingsolution may be concentrated to remove excess solvent or gaseousconstituents. If distillation is employed, the ultimate amount ofdistillate collected may vary, depending on process factors including,for example, vessel size, stirring capability, and the like. By way ofgeneral guidance, the reaction solution may be distilled to about 1/10the original volume before solvent replacement is carried out. Thereaction may be sampled and assayed to determine the extent of thereaction and the wt % product in accordance with standard processtechniques. If desired, additional reaction solvent may be added orremoved to optimize reaction concentration. Preferably, the finalconcentration is adjusted to about 50 wt % at which point a slurrytypically results.

It may be preferable to add solvents directly to the reaction vesselwithout distilling the reaction mixture. Preferred solvents for thispurpose are those which may ultimately participate in the crystallinelattice as discussed above in connection with solvent exchange. Althoughthe final concentration may vary depending on desired purity, recoveryand the like, the final concentration of free base I in solution ispreferably about 4% to about 7%. The reaction mixture may be stirredfollowing solvent addition and simultaneously warmed. By way ofillustration, the reaction mixture may be stirred for about 1 hour whilewarming to about 70° C. The reaction is preferably filtered hot andwashed with either the reaction solvent, the solvent added or acombination thereof. Seed crystals may be added to any crystallizationsolution to initiate crystallization.

The various forms described herein may be distinguishable from oneanother through the use of various analytical techniques known to one ofordinary skill in the art. Such techniques include, but are not limitedto, solid state nuclear magnetic resonance (SSNMR) spectroscopy, X-raypowder diffraction (PXRD), differential scanning calorimetry (DSC),and/or thermogravimetric analysis (TGA).

One of ordinary skill in the art will appreciate that an X-raydiffraction pattern may be obtained with a measurement error that isdependent upon the measurement conditions employed. In particular, it isgenerally known that intensities in a X-ray diffraction pattern mayfluctuate depending upon measurement conditions employed and the shapeor morphology of the crystal. It should be further understood thatrelative intensities may also vary depending upon experimentalconditions and, accordingly, the exact order of intensity should not betaken into account. Additionally, a measurement error of diffractionangle for a conventional X-ray diffraction pattern is typically about0.2% or less, preferably about 0.1% (as discussed hereinafter), and suchdegree of measurement error should be taken into account as pertainingto the aforementioned diffraction angles. Consequently, it is to beunderstood that the crystal forms of the instant invention are notlimited to the crystal forms that provide X-ray diffraction patternscompletely identical to the X-ray diffraction patterns depicted in theaccompanying Figures disclosed herein. Any crystal forms that provideX-ray diffraction patterns substantially identical to those disclosed inthe accompanying Figures fall within the scope of the present invention.The ability to ascertain substantial identities of X-ray diffractionpatterns is within the purview of one of ordinary skill in the art.

The term “Form” as used herein with respect to Form A and Form E3 refersto a homogeneous crystal structure.

The term “Pattern” as used herein with respect to Pattern C materialrefers to a characteristic x-ray diffraction pattern.

The term “atazanavir bisulfate” as employed herein refers to atazanavirbisulfate as well as atazanavir sulfate.

In carrying out the process of the invention for preparing Form Acrystals of atazanavir bisulfate salt, a modified cubic crystallizationtechnique is employed wherein atazanavir free base is dissolved in anorganic solvent in which the atazanavir bisulfate salt is substantiallyinsoluble and includes acetone, a mixture of acetone andN-methylpyrrolidone, ethanol, a mixture of ethanol and acetone and thelike, to provide a solution having a concentration of atazanavir freebase within the range from about 6.5 to about 9.7% by weight, preferablyfrom about 6.9 to about 8.1% by weight atazanavir free base.

The solution of atazanavir free base is heated at a temperature withinthe range from about 35 to about 55° C., preferably from about 40 toabout 50° C., and reacted with an amount of concentrated sulfuric acid(containing from about 95 to about 100% H₂SO₄) to react with less thanabout 15%, preferably from about 5 to less than about 12%, morepreferably from about 8 to about 10% by weight of the total atazanavirfree base. Thus, the starting solution of atazanavir fee base will beinitially reacted with less than about 15%, preferably from about 5 toabout 12%, by weight of the total amount of sulfuric acid to beemployed. During the reaction, the reaction mixture is maintained at atemperature within the range from about 35 to about 55° C., preferablyfrom about 40 to about 50° C.

The reaction is allowed to continue for a period from about 12 to about60 minutes, preferably from about 15 to about 30 minutes.

The reaction mixture is seeded with crystals of Form A atazanavirbisulfate employing an amount of seeds within the range from about 0.1to about 80% by weight, preferably from about 3 to about 8% by weight,based on the weight of atazanavir free base remaining in the reactionmixture while maintaining the reaction mixture at a temperature withinthe range from about 35 to about 55° C., preferably from about 40 toabout 50° C.

The reaction is allowed to continue until crystallization begins.Thereafter, sulfuric acid is added in multiple stages at an increasingrate according to the cubic equation as described below to formatazanavir bisulfate which upon drying produces Form A crystals.

The crystal particle size and morphology of the atazanavir bisulfatesalt formed are dependent on the addition rate of the sulfuric acid,which determines the crystallization rate. It has been found that amodified “cubic” crystallization technique (acid added at an increasingrate according to a cubic equation) provides relatively larger, morewell defined atazanavir bisulfate crystals, along with a narrowerparticle size range and fewer fines, than a constant addition ratecrystallization. The slow initial acid flow rate has been shown to favorcrystal growth over secondary nucleation. Thus, as the surface areaincreases with particle size, the seed bed is able to accept theincreasing acid flow rate without inducing secondary nucleation. Theslow initial addition rate allows time for the crystals to grow larger,increasing the mean size. The cubic crystallization provides a lesscompressible filter cake, which aids in effective cake deliquoring andwashing, as well as giving a more easily dried product with fewer hardlumps than the constant addition rate crystallized product.

The cubic crystallization method employed is a temperature controlledcrystallization derived from Mullin, “Crystallization, 3^(rd) Ed.”,1993, Butterworth-Heineman, Pubs. and is defined by the followingsimplified equation: $\begin{matrix}{T = {T_{\max} - {( {T_{\max} - T_{\min}} ) \times ( \frac{time}{{time}_{total}} )^{3}}}} & (1)\end{matrix}$where

-   -   T_(max)=Starting temperature for crystallization    -   T_(min)=Ending temperature for crystallization    -   time=Elapsed time in crystallization    -   time_(total)=Total crystallization time.

Since the crystallization of atazanavir bisulfate is controlled by theaddition rate of sulfuric acid, the temperature variable is replacedwith acid volume in Equation (1). In this equation, the variablerepresenting the minimum volume is removed. $\begin{matrix}{V_{time} = {V_{total} \times ( \frac{time}{{time}_{total}} )^{3}}} & (2)\end{matrix}$where

-   -   V_(time)=Volume of sulfuric acid added during elapsed time        period    -   V_(total)=Total volume of acid representing the 90% charge    -   time=Elapsed time in crystallization    -   time_(total)=Total crystallization time.        Equation (2) is referred to as “the cubic equation.”

By controlling the crystallization rate using this expression,nucleation is controlled within acceptable limits as the systemmaintains a constant low level of supersaturation.

Form A crystals are identified by powder x-ray diffraction pattern andcrystal structure as shown in FIGS. 1 and 2, respectively.

The Form A crystals of atazanavir bisulfate or the Pattern C material aswell as Form E3 prepared as described above are the final atazanavirbisulfate and can be employed as drug products for administration topatients.

In accordance with the process of the invention, Pattern C material maybe prepared by exposing Form A crystals to water followed by drying.

In another process in accordance with the present invention, Pattern Cmaterial may be formed by exposing crystals of Form A to high relativehumidity of greater than about 95% RH, preferably from about 95 to about100% RH (water vapor), for at least 24 hours, preferably from about 24to about 48 hours.

In another embodiment of the invention, Pattern C material is preparedby wet granulating atazanavir bisulfate Form A to produce granules ofatazanavir bisulfate and then drying the granules.

In carrying out the wet granulation process, the atazanavir bisulfatewill be granulated in water and dried at a temperature within the rangefrom about 40 to about 80° C., preferably within the range from about 50to about 60° C. The drying step will be preferably carried out for atleast about 2 hours, up to about 20 hours, preferably from about 8 toabout 10 hours.

The Pattern C material may also be formed by wet granulating atazanavirbisulfate Form A in the presence of conventional pharmaceuticalexcipients, for example, one or more bulking agents, preferably lactose,one or more disintegrants, preferably crospovidone, and drying asdescribed above to form Pattern C material in admixture with theexcipients.

It is the Pattern C material, Form A or Form E3, preferably Pattern Cmaterial, which is formulated for administration in the treatment ofdiseases caused by viruses as described hereinafter.

Pattern C material is characterized by its powder x-ray diffractionpattern as shown in FIG. 3.

The Form E3 is prepared by slurrying atazanavir free base in ethanol;treating the slurry with concentrated sulfuric acid employing a molarratio of acid: free base with the range from about 1:1 to about 1.1:1,heating the resulting solution at from about 30 to about 40° C., seedingthe solution with ethanol wet E3 crystals of atazanavir sulfate,treating the mixture with heptane (or other solvent such as hexane ortoluene), filtering, and drying to yield atazanavir bisulfate Form E3(triethanol solvate).

The seeding step will employ an amount of seeds to effect formation ofE3 crystals, for example a molar ratio of atazanavir bisulfate E-3seeds:free base within the range from about 0.02:1 to about 0.04:1.

Form E3 is identified by powder x-ray diffraction pattern as shown inFIG. 7 and crystal structure as shown in FIG. 6.

In accordance with the present invention, the atazanavir in the form ofits free base is prepared by treating a solution of a protected triaminesalt of the structure

(where PG represents a protecting group such as t-butyloxycarbonyl (Boc)or trifluoroacetyl, preferably Boc, with an acid, preferablyhydrochloric acid (where Boc is used), or a base (where trifluoroacetylis used) in the presence of an organic solvent such as methylenechloride, tetrahydrofuran, or methanol, which solvent is preferablymethylene chloride, at a temperature within the range from about 25 toabout 50° C., preferably from about 30 to about 40° C., to form thetriamine acid salt, preferably the hydrogen chloride salt of thestructure

and without isolating the triamine acid salt, reacting the triamine acidsalt with an active ester of an acid of the structure

preferably the active ester of the structure

in the presence of a base such as K₂HPO₄, diisopropylethylamine,N-methylmorpholine, sodium carbonate, or potassium carbonate, preferablyK₂HPO₄, in the presence of an organic solvent such as methylenechloride, a mixture of ethyl acetate and butyl acetate, acetonitrile orethyl acetate, preferably methylene chloride, at a temperature withinthe range from about 25 to about 50° C., preferably from about 30 toabout 40° C. to form atazanavir free base.

The protected triamine starting material is prepared by reacting theepoxide

where PG is preferably Boc such asN-(tert-butyloxycarbonyl)-2(S)-amino-1-phenyl-3(R)-3,4-epoxy-butane,with the hydrazine carbamate

where PG is preferably Boc in the presence of isopropyl alcohol or otheralcohol such as ethanol or butanol.

Atazanavir bisulfate is useful for administration to a warm-bloodedanimal, especially a human being, for the treatment or prevention of adisease that is responsive to inhibition of a retroviral protease,especially a retroviral aspartate protease, such as HIV-1 or HIV-II gagprotease, for example a retroviral disease, such as AIDS or itspreliminary stages.

Atazanavir bisulfate, especially Pattern C material, Form A or Form E3,preferably Pattern C material or Form A, may be used in a method oftreating diseases caused by viruses, especially by retroviruses,especially AIDS or its preliminary stages, wherein a therapeuticallyeffective amount of atazanavir bisulfate Pattern C material, Form A orForm E3 is administered in a dose that is effective in the treatment ofsaid disease especially to a warm-blooded animal, for example a humanbeing, who on account of one of the mentioned diseases, especially AIDSor its preliminary stages, requires such treatment. The preferred doseto be administered to warm-blooded animals, for example human beings ofapproximately 70 kg body weight, is from about 3 mg to about 1.5 g,preferably from about 10 mg to about 1.25 g, for example from about 50mg to about 600 mg per person per day, divided preferably into 1 to 4single doses which may, for example, be of the same size. Usually,children receive half of the adult dose. It is preferably administeredorally.

Atazanavir bisulfate Pattern C material, Form A or Form E3 is employedfor the above described pharmaceutical uses. Suitable compositionscontaining Pattern C material or Form A or Form E3 for oraladministration include tablets, powders, capsules, and elixirs. About 10to 600 mg of active ingredient is compounded with physiologicallyacceptable vehicle, carrier, excipient, binder, preservative,stabilizer, flavoring, etc., in a unit dose form as called for byaccepted pharmaceutical practice.

Pharmaceutical compositions for oral administration can be obtained bycombining the active ingredient with solid carriers, if desiredgranulating a resulting mixture, and processing the mixture, if desiredor necessary, after the addition of appropriate excipients, intotablets, dragée cores, capsules or powders for oral use. It is alsopossible for the active ingredients to be incorporated into plasticcarriers that allow the active ingredients to diffuse or be released inmeasured amounts.

The bulking agents or fillers will be present in the pharmaceuticalcompositions of the invention in an amount within the range from about 0to about 95% by weight and preferably from about 10 to about 85% byweight of the composition. Examples of bulking agents or fillerssuitable for use herein include, but are not limited to, cellulosederivatives such as microcrystalline cellulose or wood cellulose,lactose, sucrose, starch, pregelatinized starch, dextrose, mannitol,fructose, xylitol, sorbitol, corn starch, modified corn starch,inorganic salts such as calcium carbonate, calcium phosphate, dicalciumphosphate, calcium sulfate, dextrin/dextrates, maltodextrin,compressible sugars, and other known bulking agents or fillers, and/ormixtures of two or more thereof, preferably lactose.

A binder will be optionally present in the pharmaceutical compositionsof the invention in an amount within the range from about 0 to about 20%weight, preferably from about 1 to about 10% by weight of thecomposition. Examples of binders suitable for use herein include, butare not limited to, hydroxypropyl cellulose, corn starch, pregelatinizedstarch, modified corn starch, polyvinyl pyrrolidone (PVP) (molecularweight ranging from about 5,000 to about 80,000, preferably about40,000), hydroxypropylmethyl cellulose (HPMC), lactose, gum acacia,ethyl cellulose, cellulose acetate, as well as a wax binder such ascarnauba wax, paraffin, spermaceti, polyethylenes or microcrystallinewax, as well as other conventional binding agent and/or mixtures by twoor more thereof, preferably hydroxypropyl cellulose.

The disintegrant will be optionally present in the pharmaceuticalcomposition of the invention in an amount within the range from about 0to about 20% by weight, preferably from about 0.25 to about 15% byweight of the composition. Examples of disintegrants suitable for useherein include, but are not limited to, croscarmellose sodium,crospovidone, potato starch, pregelatinized starch, corn starch, sodiumstarch glycolate, microcrystalline cellulose, or other knowndisintegrant, preferably croscarmellose sodium.

The lubricant will be optionally present in the pharmaceuticalcomposition of the invention in an amount within the range from about0.1 to about 4% by weight, preferably from about 0.2 to about 2% byweight of the composition. Examples of tableting lubricants suitable foruse herein include, but are not limited to, magnesium stearate, zincstearate, calcium stearate, talc, carnauba wax, stearic acid, palmiticacid, sodium stearyl fumarate or hydrogenated vegetable oils and fats,or other known tableting lubricants, and/or mixtures of two or morethereof, preferably magnesium stearate.

Capsules are hard gelatin capsules and also soft, sealed capsules madeof gelatin and a plasticizer, such as glycerol or sorbitol. The hardgelatin capsules may include the active ingredient in the form ofgranules, for example with fillers, such as lactose, binders, such asstarches, crospovidone and/or glidants, such as talc or magnesiumstearate, and if desired with stabilizers. In soft gelatin capsules theactive ingredient is preferably dissolved or suspended in suitable oilyexcipients, such as fatty oils, paraffin oil or liquid polyethyleneglycols, it likewise being possible for stabilizers and/or antibacterialagents to be added.

The following examples represent preferred embodiments of the invention.

EXAMPLE 11-[4-(Pyridin-2-yl)phenyl]-5(S)-2,5-bis{[N-(methoxycarbonyl)-L-tert-leucinyl]amino}-4-(S)-hydroxy-6-phenyl-2-azahexane,Bisulfate salt (Form A) (Atazanavir bisulfate—Form A)

A.

(1-[4-(Pyridin-2-yl)phenyl]-5(S)-2,5-bis[tert-butyloxycarbonyl)amino]-4(S)-hydroxy-6-phenyl-2-azahexane.3HCl(Triamine.3HCl Salt))

To a 1000 mL, 3-neck, round-bottom flask fitted with mechanical stirrer,nitrogen inlet and temperature probe was added the protected triamine1-[4-(pyridin-2-yl)phenyl]-5(S)-2,5-bis[tert-butyloxycarbonyl)amino]-4(S)-hydroxy-6-phenyl-2-azahexane

(100 g, 0.178 mol), and CH₂Cl₂ (500 mL; 5 mL/g of protected triamineinput) (prepared as described in Z. Xu et al., Process Research andDevelopment for an Efficient Synthesis of the HIV Protease InhibitorBMS-232,632, Organic Process Research and Development, 6, 323-328(2002)) and the resulting slurry was agitated while maintaining thetemperature at from about 5 to about 22° C.

Concentrated hydrochloric acid (68 mL, 0.82 mole, 4.6 eq.) was added tothe reaction mixture at a rate such that the temperature of the reactionmixture remained between 5 and 30° C. The reaction mixture was heated to30 to 40° C. and agitated until the reaction was judged complete by HPLCassay.

Water was added (70-210 mL, 0.7-2.1 mL/g protected triamine input) tothe reaction mixture, the reaction mixture was agitated for 15 minutesand the phases were allowed to separate. The upper, product(triamine.3HCl salt)—rich aqueous oil was transferred to an additionfunnel.

To a 3000 mL, 3-neck round bottom flask fitted with mechanical stirrer,addition funnel, nitrogen inlet, and temperature probe was addedN-methoxycarbonyl-L-tert-leucine (77.2 g, 0.408 mol, 2.30 eq.),1-hydroxybenzotriazole (HOBT) (60.8 g, 0.450 mol, 2.53 eq.), and N-ethylN′-dimethylaminopropyl carbodiimide (EDAC) (82.0 g, 0.430 mol, 2.42eq.), followed by CH₂Cl₂ (880 mL; 8.8 mL/g of protected triamine input)and the mixture was stirred at ambient temperature (18-25° C.) untilformation of the active ester is complete, as judged by HPLC.

C.1-[4-(Pyridin-2-yl)phenyl]-5(S)-2,5-bis{[N-(methoxycarbonyl)-L-tert-leucinyl]amino}-4(S)-hydroxy-6-phenyl-2-azahexane(atazanavir free base)

Anhydrous dibasic potassium phosphate (K₂HPO₄; 226 g., 1.30 mol, 7.30eq. wrt protected triamine) was dissolved in 1130 mL of water (11.3 mL/gof protected amine; 5 mL/g of K₂HPO₄).

The K₂HPO₄ solution was added to the active ester solution prepared inPart B. To the stirred active ester/aqueous K₂HPO₄ mixture was slowlyadded the aqueous solution of Part A hydrogen chloride salt over aperiod of 1.5 to 2.0 h while maintaining agitation and a pot temperaturebetween 5 and 20° C.

After the addition of the solution of the Part A hydrogen chloride saltwas complete, the reaction mixture (coupling reaction) was heated to30-40° C. and agitated until the coupling reaction was judged completeby HPLC assay.

The coupling mixture was cooled to 15 to 20° C. and the lower, productrich organic phase was separated from the upper, spent aqueous phase.

The product rich organic phase was washed with 1M NaH₂PO₄ (880 mL;pH=1.5; 8.8 mL/g of protected triamine input; 5 mole eq. wrt protectedtriamine), the phases were allowed to separate, and the spent aqueousphase was removed.

The washed product rich organic phase was stirred with 0.5 N NaOH (800mL; 8 mL/g of protected triamine input) until HPLC assay of the richorganic phase showed the active esters to be below 0.3 I.I. each. Thephases were allowed to separate and the spent aqueous phase was removed.

The rich organic phase was washed with 5% NaH₂PO₄ (450 mL, 4.5 mL/g ofprotected triamine input; pH=4.3), the phases were allowed to separateand the spent aqueous phase was removed.

The rich organic phase was washed with 10 w/v % NaCl (475 mL, 4.75 mL/gof protected triamine input) and the spent aqueous phase was removed.

The concentration of title free base in solution was 120 to 150 mg/mLwith an in-process calculated yield of 95-100 mol %.

D. Solvent Exchange from CH₂Cl₂ into Acetone/N-Methylpyrrolidone

To the rich Part C free base solution in a 3000 mL, 3-neck round-bottomflask fitted with mechanical stirrer, temperature probe, anddistillation condenser, was added N-methylpyrrolidone (148 mL; 1.25 mL/gof Part C free base based on in-process quantification assay). Thesolution was concentrated to ca. 360 mL (2.5-3.5 mL/g of Part C freebase) using a jacket temperature of 70° C. or less; 500 mL of acetone(4-5 mL/g of Part C free base) was added to the concentrated solutionand the mixture was distilled to a volume of about 400 mL or less.

The acetone addition and distillation were repeated until in-processassay indicated the CH₂Cl₂ level had reached the target endpoint. Atcrystallization volume, the CH₂Cl₂ content in the rich organic solutionwas 0.77 v/v %. Acetone was added to the concentrated free base solutionto reach a total solution of 16 mL/g of free base. The bath temperaturewas maintained at 40-50° C. to prevent crystallization of free base. Thesolution was polish filtered through a 10-micron or finer filter whilemaintaining the temperature at 40 to 50° C. The polish filter was rinsedwith acetone (125 mL, 1.0 mL/g of free base) and the rinse was added tothe rich free base acetone/N-methylpyrrolidone solution which was usedin the next step.

E. 1-[4-(Pyridin-2-yl)phenyl]-5(S)-2,5-bis{[N-(methoxycarbonyl)-L-tert-leucinyl]amino}-4(S)-hydroxy-6-phenyl-2-azahexanebisulfate salt

About 10% (2 g) of the total charge of concentrated sulfuric acid (19 g,1.10 eq.) was added to the free base acetone/N-methylpyrrolidonesolution of Part D, while maintaining the temperature at 40-50° C., viasubsurface addition.

The reaction mixture was seeded with 5.0 wt % (wrt calculated free basein solution) of bisulfate salt. The seeded mixture was agitated at40-50° C. for at least 30 minutes during which time the bisulfate saltbegan crystallizing as evidenced by the mixture increasing in opacityduring this time.

The remaining sulfuric acid (17.8 g) was added over ca. 5 h in fivestages according to the following protocol, defined by a cubic equation,while keeping the temperature at 40-50° C.

The rate of each addition stage was determined according to the cubicequation described hereinbefore and is shown in the table below. TABLE 1Stage mL/kg/h mL(H₂SO₄)/h g(H₂SO₄)/h Duration (min) 1 4.62 0.579 1.06560 2 6.93 0.868 1.597 60 3 16.55 2.073 3.814 60 4 30.26 3.790 6.974 60 548.47 6.071 11.171 23

After addition of H₂SO₄ was complete, the slurry was cooled to 20-25° C.for at least 1 h with agitation. The slurry was agitated at 20-25° C.for at least 1 h. The bisulfate salt was filtered and the mother liquorwas recycled as needed to effect complete transfer. The filter cake waswashed with acetone (5-10 mL/g of free base; 1200 mL acetone). Thebisulfate salt was dried at NMT 55° C. under vacuum until the LOD<1% toproduce a crystalline material.

The crystalline product was analyzed by PXRD, DSC and TGA patterns andSSNMR spectrum and found to be (non-solvated) Form A crystals of thetitle bisulfate (see FIGS. 1 to 5). TABLE 2 Table of CrystallographicData Form A T° C. a(Å) b(Å) c(Å) α° β° γ° V(Å³) Z′ sg dcalc R +229.861(5) 29.245(6) 8.327(2) 93.56(2) 114.77(3) 80.49(3) 2150(2) 2 P11.240 0.06T = temp(° C.) for the crystallographic data.Z′ = number of drug molecules per asymmetric unit

TABLE 3 Table Of Fractional Parameters and Their Estimated StandardDeviations for Form A Atom x y z B(A2) S1 0.3230(4) 0.5467(1) 0.5608(5)8.0(1) O100 0.431(1) 0.5060(3) 0.649(1) 11.1(3) O102 0.335(1) 0.5498(4)0.383(1) 12.0(4) O103 0.360(1) 0.5877(4) 0.655(2) 12.0(4) O104 0.176(1)0.5384(4) 0.528(1) 11.8(4) S51 0.6177(4) 0.4505(1) 0.4003(5) 7.2(1) O1500.596(1) 0.4430(4) 0.564(1) 12.5(4) O152 0.518(1) 0.4921(4) 0.317(1)13.8(4) O153 0.588(1) 0.4121(3) 0.289(2) 12.2(4) O154 0.768(1) 0.4587(4)0.454(1) 12.1(4) O4 0.6985(7) 0.1753(3) 0.6456(9) 5.7(2) O7 0.1687(8)0.1941(3) 0.3411(9) 6.5(2) O11 −0.0352(7) 0.2482(3) 0.0308(8) 5.7(2) O140.2280(7) 0.1769(3) −0.233(1) 6.1(2) O15 0.0399(8) 0.1335(3) −0.330(1)6.4(2) O17 0.6169(7) 0.2821(3) 0.963(1) 7.1(2) O18 0.3750(7) 0.2905(3)0.9136(9) 6.2(2) N2 0.5015(9) 0.2182(3) 0.902(1) 4.5(2) N5 0.4642(8)0.1647(3) 0.6001(9) 4.2(2) N9 0.2317(9) 0.2788(3) 0.256(1) 5.1(2) N100.1820(9) 0.2760(3) 0.069(1) 4.6(2) N13 −0.0148(8) 0.2083(3) −0.280(1)4.6(2) N39 −0.087(1) 0.5265(3) 0.272(1) 6.1(3) C1 0.491(1) 0.2627(4)0.924(1) 5.5(3) C3 0.6381(9) 0.1908(3) 0.892(1) 4.0(2) C4 0.600(1)0.1764(4) 0.702(1) 4.6(3) C6 0.420(1) 0.1551(4) 0.403(1) 5.1(3) C70.295(1) 0.1936(4) 0.297(1) 5.1(3) C8 0.357(1) 0.2400(4) 0.346(2) 5.4(3)C11 0.051(1) 0.2592(4) −0.028(1) 4.9(3) C12 0.024(1) 0.2531(4) −0.223(1)4.5(3) C14 0.094(1) 0.1732(4) −0.280(1) 4.7(3) C16 0.146(2) 0.0943(5)−0.342(2) 10.9(5) C19 0.616(1) 0.3313(4) 0.996(2) 8.1(4) C20 0.701(1)0.1485(4) 1.025(1) 5.8(3) C21 0.842(1) 0.1219(5) 1.007(2) 7.9(4) C220.583(2) 0.1160(5) 0.997(2) 8.0(4) C23 0.748(2) 0.1713(5) 1.215(1)8.2(4) C24 0.365(1) 0.1079(4) 0.356(2) 6.6(4) C25 0.484(1) 0.0691(4)0.470(1) 6.5(3) C26 0.643(2) 0.0684(5) 0.520(2) 8.4(5) C27 0.753(2)0.0293(6) 0.622(2) 11.4(6) C28 0.709(3) −0.0044(7) 0.691(3) 15.0(9) C290.553(2) −0.0032(5) 0.644(2) 14.2(7) C30 0.441(2) 0.0343(5) 0.534(2)10.8(4) C31 0.291(1) 0.3229(4) 0.311(2) 5.7(3) C32 0.177(1) 0.3650(4)0.259(1) 5.4(3) C33 0.224(1) 0.4064(4) 0.262(2) 6.3(3) C34 0.122(1)0.4487(5) 0.233(2) 6.9(4) C35 −0.031(1) 0.4469(4) 0.189(1) 4.8(3) C36−0.081(1) 0.4043(4) 0.180(1) 5.6(3) C37 0.019(1) 0.3629(4) 0.218(1)5.4(3) C38 −0.136(1) 0.4918(4) 0.170(1) 5.3(3) C40 −0.170(1) 0.5683(4)0.279(2) 7.8(4) C41 −0.318(2) 0.5736(5) 0.158(2) 9.1(5) C42 −0.376(2)0.5403(5) 0.035(2) 9.0(5) C43 −0.283(1) 0.4964(5) 0.039(2) 8.1(4) C44−0.096(1) 0.2937(4) −0.345(1) 6.2(3) C45 −0.258(1) 0.2901(5) −0.366(2)8.5(4) C46 −0.085(2) 0.2890(6) −0.530(2) 10.8(5) C47 −0.057(2) 0.3393(5)−0.265(2) 8.9(5) O54 0.2347(7) 0.8167(3) 0.8392(8) 5.3(2) O57 0.7713(8)0.7950(3) 1.0561(9) 5.9(2) O61 0.9725(7) 0.7436(3) 0.9141(8) 5.3(2) O640.7062(7) 0.8164(3) 0.427(1) 5.9(2) O65 0.8911(8) 0.8598(2) 0.535(1)6.1(2) O67 0.3150(8) 0.7090(3) 1.184(1) 6.4(2) O68 0.5587(9) 0.6986(3)1.377(1) 6.6(2) N52 0.4313(9) 0.7713(3) 1.271(1) 4.9(2) N55 0.4709(8)0.8265(3) 1.0332(9) 4.2(2) N60 0.7555(8) 0.7179(3) 0.728(1) 4.6(2) N630.9491(8) 0.7852(3) 0.601(1) 4.4(2) N89 1.026(1) 0.4719(3) 0.711(1)6.0(3) C51 0.442(1) 0.7247(4) 1.282(1) 5.4(3) C53 0.296(1) 0.7996(4)1.141(1) 5.1(3) C54 0.3347(9) 0.8159(3) 0.989(1) 4.1(3) C56 0.519(1)0.8353(4) 0.887(1) 4.7(3) C57 0.644(1) 0.7959(4) 0.886(1) 4.5(3) C580.587(1) 0.7494(4) 0.854(1) 5.2(3) C61 0.884(1) 0.7334(4) 0.766(1)4.2(3) C62 0.914(1) 0.7392(4) 0.603(1) 4.4(3) C64 0.839(1) 0.8196(4)0.513(1) 4.6(3) C66 0.785(2) 0.8996(5) 0.433(3) 12.1(7) C69 0.323(1)0.6588(4) 1.202(2) 8.8(5) C70 0.237(1) 0.8409(4) 1.232(1) 5.6(3) C710.092(1) 0.8701(5) 1.080(2) 7.6(4) C72 0.352(1) 0.8744(4) 1.328(2)7.1(4) C73 0.187(1) 0.8195(6) 1.362(1) 8.9(4) C74 0.570(1) 0.8825(4)0.907(2) 6.4(3) C75 0.450(1) 0.9206(4) 0.919(1) 6.3(3) C76 0.296(2)0.9236(5) 0.813(2) 8.1(4) C77 0.188(2) 0.9614(6) 0.826(2) 11.2(5) C780.244(2) 0.9942(6) 0.960(2) 15.2(7) C79 0.405(3) 0.9935(6) 1.062(2)13.9(7) C80 0.504(2) 0.9552(4) 1.043(2) 9.3(5) C81 0.644(1) 0.6672(4)0.832(2) 6.2(3) C82 0.762(1) 0.6266(3) 0.839(1) 4.7(3) C83 0.723(1)0.5934(4) 0.696(2) 6.1(3) C84 0.822(1) 0.5547(4) 0.695(2) 5.9(3) C850.967(1) 0.5478(4) 0.828(1) 5.0(3) C86 1.009(1) 0.5783(4) 0.971(2)6.6(4) C87 0.908(1) 0.6184(4) 0.971(2) 6.4(4) C88 1.076(1) 0.5070(4)0.827(1) 5.5(3) C90 1.111(1) 0.4326(4) 0.690(2) 7.4(4) C91 1.258(2)0.4262(5) 0.792(2) 7.8(4) C92 1.324(2) 0.4578(5) 0.918(2) 8.7(5) C931.230(1) 0.4994(5) 0.936(2) 6.9(4) C94 1.038(1) 0.7005(4) 0.584(1)4.8(3) C95 1.196(1) 0.7055(4) 0.717(2) 6.7(4) C96 1.021(2) 0.7049(5)0.392(2) 8.9(4) C97 0.998(1) 0.6536(4) 0.614(2) 7.6(4) N59 0.7084(8)0.7114(3) 0.866(1) 5.1(2) H391 0.047 0.523 0.383 6.0* H891 0.931 0.4770.646 5.8* H15′ 0.491 0.471 0.600 3.8* H15″ 0.440 0.512 0.322 4.6*Most hydrogens have been omitted; only the hydrogens on N9 and the acidare included.Anisotropically refined atoms are given in the form of the isotropicequivalent displacement parameter defined as:(4/3)*[a2*B(1,1)+b2*B(2,2)+c2*B(3,3)+ab(cos gamma)*B(1,2)x+ac(cosbeta)*B(1,3)+bc(cos alpha)*B(2,3)].

Form A is characterized by a differential scanning calorimetrythermogram having an endotherm typically within the range from about165.6° C. to about 200.9° C. as shown in FIG. 3.

Form A is also characterized by a thermal gravimetric analysis curvehaving a negligible weight loss up to about 100 to 150° C.

The crystals produced by cubic crystallization where H₂SO₄ is added atan increasing rate according to the cubic equation described above wererelatively larger and more well-defined, and had a narrower particlesize range and fewer fines, than crystals obtained employing constantaddition rate crystallization.

The filter cake obtained using the cubic crystallization technique wasless compressible than that obtained using constant addition ratecrystallization, which aided in effective cake deliquoring and washingand produced a homogeneous product. TABLE 4 Carbon-13 SSNMR ChemicalShifts for Form A, measured relative to TMS (tetramethyl silane) δ/ppm26.9 27.5 33.9 37.7 49.2 53.5 62.7 63.3 66.0 69.2 69.5 122.6 123.7 125.3126.1 127.6 128.5 129.4 131.1 134.4 138.8 139.7 140.6 143.2 143.9 149.9150.3 153.9 159.3 172.0

EXAMPLE 2 Atazanavir Bisulfate—Pattern C Material

Method A:

Form A crystals of atazanavir bisulfate (prepared as described inExample 1) (25.33 g) were suspended in 200 mL of water and the mixturewas stirred mechanically to produce a thick gel which was dried.

The dried mixture was ground with a spatula to produce Pattern Cmaterial. A powder X-ray diffraction pattern of Pattern C material isshown in FIG. 6.

Method B:

Form A crystals of atazanavir bisulfate was wet granulated using asufficient amount of water (about 40% w/w) in a suitablemixer-granulator. The wet mass was dried in an oven. The product wassized using a suitable screen. The x-ray diffraction pattern of theresultant product is consistent with Pattern C material as shown in FIG.6.

Pattern C is characterized by the differential scanning calorimetrythermogram shown in FIG. 7 having an endotherm typically in the rangefrom about 76.7 to about 96.6° C. and from about 156.8 to about 165.9°C.

Pattern C is also characterized by a thermal gravimetric analysis curvehaving a weight loss of about 2.4% at about 125° C. and about 4.4% atabout 190° C. as shown in FIG. 8.

EXAMPLE 3 Atazanavir Bisulfate—Form E3 (Triethanol Solvate)

Atazanavir free base (prepared as described in Example 1, Part C) (3.0g, 4.26 mmol) was slurried in dry, 200 proof ethanol (20.25 mL, 6.75mL/g of free base) in a 100 mL, 3-neck round-bottom flask fitted with amechanical stirrer, temperature probe, and a pressure-equalizing liquidaddition funnel.

Concentrated H₂SO₄ (0.25 mL, 0.46 g, 4.69 mmol, 1.1 eq.) was added tothe slurry of atazanavir free base which was maintained at 20-25° C. Theresulting solution (KF of 0.2 to 1.0% water) was polish filtered(Whatman #1 paper), the filter rinsed with 2.25 mL of absolute ethanoland the rinse added to the filtered solution. The solution was heated to37° C. and seeded with 10 mg of amorphous atazanavir bisulfate derivedfrom Form E3 crystals (by exposing Form E3 crystals to ambienttemperature), and the mixture was agitated for 15 min. Heptane (380 mL,8.25 mL/g of free base) was added over 1 hour. The resultingcrystallization mixture was agitated for 8 h at 15-25° C. Crystallizedatazanavir bisulfate was filtered on a Büchner funnel. The product cakewas washed with 184 mL (4 mL/g of free base) of 1:1 ethanol: heptane.The product cake was washed with 46 mL (1 mL/g of free base) of heptane.The resulting product was dried under vacuum at 40-50° C. until it hadan LOD=0.97%. The yield of product was 47.7 g (0.0594 mol, 74.3 mol %)of atazanavir bisulfate Form E3 (triethanol solvate) with HPLC HI=100.0(see FIGS. 9 and 10). TABLE 5 Table of Crystallographic Data Form E3 T°C. a(Å) b(Å) c(Å) α° β° γ° V(Å³) Z′ sg dcalc R −23 10.749(5) 13.450(4)9.250(2) 98.33(2) 95.92(3) 102.82(3) 1277(2) 1 P1 1.223 0.06T = temp(° C.) for the crystallographic data.Z′ = number of drug molecules per asymmetric unit

TABLE 6 Table of Fractional Parameters and Their Estimated StandardDeviations for Form E3 Occupany if not Atom x y z B(A2) equal to 1 S99  0.5568(1)   0.0760(1)   0.5936(1) 3.45(2) O1   0.4200(5)   0.5541(4)  0.8496(5)  6.9(1) O2   0.2889(5)   0.6016(4)   1.0066(6)  8.1(1) O4  0.7004(4)   0.4509(3)   1.0233(4) 4.23(8) O8   0.2913(4)   0.2932(3)  1.1074(4) 4.23(8) O12   0.1057(4)   0.1088(3)   0.9299(4) 4.16(8) O15′   0.329(1) −0.0602(9)    1.064(1)  4.8(3)* .3 O15″    0.324(2) −0.156(1)    1.003(2)  3.2(3)* .17 O15   0.3312(7) −0.1150(6)  1.0380(8)  4.9(1)* .53 O16   0.1810(5) −0.1433(3)   1.1819(4)  5.7(1)O86    0.391(1)   0.6646(7)   0.6196(9) 11.5(4) O89   0.3714(7)  0.5646(5)   0.3408(6)  6.5(2) O90   0.7502(4)   0.2721(3)   0.8957(5)4.99(9) O95   0.4984(4)   0.0446(3)   0.7188(4) 4.50(8) O96   0.6644(4)  0.0315(3)   0.5660(4) 4.83(8) O97   0.4651(4)   0.0667(3)   0.4636(4)5.08(9) O98   0.6112(5)   0.1957(3)   0.6332(5)  5.9(1) N2   0.4938(5)  0.6229(3)   1.0921(5)  4.8(1) N5   0.5365(4)   0.4385(3)   1.1609(4)3.16(8) N10   0.2952(4)   0.2239(3)   0.8056(4) 3.17(8) N11   0.2716(4)  0.1163(3)   0.7961(4) 3.08(8) N14   0.1336(5) −0.0874(4)   0.9743(5) 4.9(1) N38 −0.2764(4)   0.0574(3)   0.2878(4) 3.24(8) C1   0.4011(6)  0.5893(4)   0.9712(7)  5.3(1) C3   0.6225(5)   0.6026(4)   1.0813(5) 3.9(1) C4   0.6231(5)   0.4896(3)   1.0873(5) 3.19(9) C6   0.5220(5)  0.3284(3)   1.1691(5) 3.14(9) C8   0.4026(5)   0.2632(3)   1.0653(5)3.21(9) C9   0.4165(5)   0.2747(4)   0.9050(5)  3.6(1) C12   0.1740(5)  0.0661(4)   0.8596(5)  3.4(1) C13   0.1592(5) −0.0523(4)   0.8367(5) 3.8(1) C15   0.2248(6) −0.1124(5)   1.0627(6)  4.6(1) C17   0.2720(9)−0.1732(6)   1.2842(7)  7.3(2) C18   0.1818(9)   0.5715(9)    0.894(1)11.2(3) C19   0.7292(7)   0.6818(4)   1.1928(7)  5.8(2) C20    0.725(1)  0.7914(6)    1.169(1) 10.7(3) C21   0.8613(9)   0.6645(8)    1.165(1)10.5(3) C22    0.710(1)   0.6694(7)   1.3507(8) 10.2(3) C23   0.5158(5)  0.3135(4)   1.3298(5)  3.8(1) C24   0.6305(6)   0.3765(4)   1.4359(5) 4.0(1) C25   0.7519(7)   0.3708(6)   1.4192(7)  6.1(2) C26   0.8581(7)  0.4279(7)   1.5213(9)  7.9(2) C27   0.8398(8)   0.4935(6)   1.6375(8) 8.6(2) C28    0.715(1)   0.5002(6)   1.6576(7)  8.0(2) C29   0.6112(8)  0.4430(5)   1.5589(6)  6.0(2) C30   0.3043(5)   0.2519(4)   0.6582(5) 3.6(1) C31   0.1813(5)   0.2051(4)   0.5532(5)  3.4(1) C32   0.0645(5)  0.2123(4)   0.5934(5)  3.9(1) C33 −0.0489(5)   0.1725(4)   0.4957(5) 3.8(1) C34 −0.0441(5)   0.1243(4)   0.3503(5) 3.16(9) C35   0.0756(5)  0.1176(4)   0.3097(5)  3.9(1) C36   0.1867(5)   0.1568(4)   0.4095(5) 3.9(1) C37 −0.1615(5)   0.0853(4)   0.2417(4) 3.11(9) C39 −0.3885(5)  0.0247(4)   0.1969(5)  3.9(1) C40 −0.3891(5)   0.0200(4)   0.0470(5) 4.2(1) C41 −0.2737(6)   0.0469(4) −0.0057(5)  4.1(1) C42 −0.1596(5)  0.0781(4)   0.0890(5)  3.7(1) C43   0.0488(6) −0.1114(4)   0.7094(6) 4.6(1) C44 −0.0819(7) −0.0958(6)   0.7378(9)  6.8(2) C45   0.0496(9)−0.2266(5)   0.6929(9)  7.8(2) C46   0.0797(8) −0.0738(5)   0.5667(7) 6.2(2) C84    0.569(1)   0.7880(9)    0.725(1)  6.3(3) C85    0.448(1)  0.7726(9)    0.673(2)  8.4(4) C87    0.204(1)    0.449(1)    0.405(2)10.6(4) C88    0.240(1)    0.517(1)    0.316(1)  8.6(3) C91   0.8826(7)  0.2919(5)   0.8896(8)  5.8(2) C92   0.9613(7)   0.3439(6)    1.035(1) 7.8(2) H381  −0.275    0.053    0.403  3.2 H891    0.397    0.602   0.446  6.6 H981    0.658    0.219    0.717  6.6Most hydrogens have been omitted; only the hydrogens on N9 and the acidare included.

Anisotropically refined atoms are given in the form of the isotropicequivalent displacement parameter defined as:(4/3)*[a2*B(1,1)+b2*B(2,2)+c2*B(3,3)+ab(cos gamma)*B(1,2)x+ac(cosbeta)*B(1,3)+bc(cos alpha)*B(2,3)].

Form E3 is characterized by the differential scanning calorimetrythermogram having an endotherm typically within the range from about89.4 to about 96.6 as shown in FIG. 11.

Form E3 is also characterized by a thermal gravimetric analysis curvehaving a weight loss of about 14.7% at about 150° C. as shown in FIG.11.

EXAMPLE 4

Atazanavir bisulfate Pattern C capsule formulations having the followingcompositions were prepared as described below. 50-mg 100-mg 200-mg StockCapsule Capsule Capsule Granulation^(a) (mg/ (mg/ (mg/ Ingredient (%w/w) Capsule) Capsule) Capsule) Atazanavir bisulfate 63.2 56.84^(b)113.67^(b) 227.34^(b) Lactose, Monohydrate, 30.4 27.33^(c)  54.69^(c)109.35^(c) NF Crospovidone, NF 6.0  5.39  10.79  21.58 MagnesiumStearate, 0.4  0.36^(d)  0.72^(d)  1.44^(d) NF Purified Water, USPq.s.^(e) q.s.^(e) q.s.^(e) q.s.^(e) or Water for Injection, USP Size #4Capsule — 1 Each — — Size #2 Capsule — — 1 Each — Size #0 Capsule — — —1 Each Total Fill Weight 100.0 89.9 179.9 359.7^(a)Atazanavir bisulfate Stock Granulation for Capsules (55.5% w/w asthe Free Base) was used to manufacture the 50 mg, 100 mg, and 200 mgcapsules.^(b)This amount is expressed in terms of atazanavir bisulfate at 100%potency, and is equal to 55.5% w/w as the Free Base.^(c)The amount of lactose, hydrous will vary depending on the purity ofatazanavir bisulfate and the amount of magnesium stearate used.^(d)The amount of magnesium stearate used may vary from 0.4% w/w to 0.8%w/w.^(e)This is used for processing only and is removed by drying.

The stock granulation of atazanavir bisulfate was prepared as follows,in which Pattern C material was formed.

Atazanavir bisulfate Form A, lactose hydrous, and a portion ofcrospovidone (3% by weight of total crospovidone present) were mixed ina planetary mixer. The resulting blend was wet granulated with purifiedwater to convert Form A to Pattern C material. The wet granulation wasdried in a tray dryer and was sized using a hammer mill. The remainingcrospovidone was added to the milled granulation and the mixture wasmixed in a PK V-blender. Magnesium stearate was added and the mixturewas mixed until a substantially uniform stock granulation was formed.

The appropriate weight of stock granulations were filled into capsulesto produce 50 mg, 100 mg and 200 mg capsules containing atazanavirbisulfate.

EXAMPLE 5

Atazanavir bisulfate Form A material powder for oral use formulationhaving the following composition is prepared as described below.Ingredients Amount (% w/w) Atazanavir Bisulfate Form A 3.79 Aspartame,NF 10.00 Sucrose, NF 81.21 Orange vanilla flavor 5.00

Atazanavir bisulfate Form A is mixed with aspartame, orange vanillaflavor and sucrose in a suitable mixer. The mixture is milled using ahammer mill, followed by a second mixing operation to obtain a uniformmixture. The product is filled into high density polyethylene bottles.

1. A process for preparing atazanavir bisulfate in the form of Form Acrystals, which comprises reacting a solution of atazanavir free base inan organic solvent, in which the bisulfate salt of atazanavir issubstantially insoluble, with a first portion of concentrated sulfuricacid in an amount to react with less than about 15% by weight of theatazanavir free base, adding seeds of Form A crystals of atazanavirbisulfate to the reaction mixture, as crystals of atazanavir bisulfateform, adding additional concentrated sulfuric acid in multiple stages toeffect formation of atazanavir bisulfate crystals, and drying theatazanavir bisulfate to form Form A crystals.
 2. The process as definedin claim 1 wherein the solution of atazanavir free base is initiallyreacted with from about 5 to about 15% by weight of the total amount ofsulfuric acid employed.
 3. The process as defined in claim 1 wherein thesolution of atazanavir free base is initially reacted with from about 8to about 12% by weight of the total amount of sulfuric acid employed. 4.The process as defined in claim 1 wherein the atazanavir free base isreacted with the first portion of sulfuric acid at a temperature withinthe range from about 35 to about 55° C.
 5. The process as defined inclaim 1 wherein the solution of atazanavir free base is heated to atemperature within the range from about 35 to about 55° C. before it isreacted with sulfuric acid.
 6. The process as defined in claim 1 whereinthe reaction mixture of atazanavir free base and sulfuric acid is seededwith from about 0.1 to about 80 weight % of Form A crystals based on theweight of atazanavir free base.
 7. The process as defined in claim 1wherein the seeded reaction mixture is heated at a temperature withinthe range from about 35 to about 55° C.
 8. The process as defined inclaim 1 wherein the organic solvent for the atazanavir free base isacetone, a mixture of acetone and N-methylpyrrolidone, ethanol, or amixture of ethanol and acetone.
 9. Atazanavir bisulfate Pattern Cmaterial.
 10. The compound as defined in claim 9 which is Pattern Cmaterial atazanavir bisulfate characterized by the powder x-raydiffraction pattern substantially in accordance with that shown in FIG.6.
 11. The compound as defined in claim 9 which is characterized by adifferential scanning calorimetry thermogram substantially in accordancewith that shown in FIG.
 7. 12. The compound as defined in claim 9 whichis characterized by a thermal gravimetric analysis curve substantiallyin accordance with that shown in FIG.
 8. 13. The compound as defined inclaim 9 prepared by suspending Form A crystals of atazanavir bisulfatein water or subjecting Form A crystals of atazanavir bisulfate to arelatively high humidity of at least about 95% RH for at least 24 hoursor wet granulating Form A crystals of atazanavir bisulfate and thendrying.
 14. Pattern C prepared by the process of claim
 24. 15. Thecompound as defined in claim 9 in the form of a pharmaceuticalcomposition prepared by mixing Form A crystals of atazanavir bisulfatewith one or more formulating excipients and water followed by drying.16. Form E3 of atazanavir bisulfate.
 17. The compound as defined inclaim 16 prepared as a triethanolate solvate of atazanavir bisulfate.18. The compound as defined in claim 16 as characterized by a powderX-ray diffraction pattern substantially in accordance with that shown inFIG.
 9. 19. The compound as defined in claim 16 having the crystalstructure substantially shown in FIG.
 10. 20. The compound as defined inclaim 16 which is characterized by fractional atomic coordinatessubstantially as listed in Table
 6. 21. The compound as defined in claim16 which is characterized by crystallographic data substantially equalto the following: Cell dimensions: a=10.749(5)Å b=13.450(4)Å c=9.250(2)Åα=98.33(2)° β=95.92(3)° γ=102.82(3)° Space group P1 Molecules/asymmetricunit 1 wherein said crystalline form is at about −23° C.
 22. Thecompound as defined in claim 16 which is characterized by a differentialscanning calorimetry thermogram data substantially in accordance withthat shown in FIG.
 11. 23. The compound as defined in claim 16 which ischaracterized by a thermal gravimetric analysis curve substantially inaccordance with that shown in FIG.
 11. 24. A process for preparingatazanavir bisulfate Pattern C material as defined in claim 9, whichcomprises (a) suspending crystals of Form A atazanavir bisulfate inwater and drying the suspension to form Pattern C material; or (b)subjecting crystals of Form A atazanavir bisulfate to high relativehumidity of greater than 95% RH for at least 24 hours to form Pattern Cmaterial; or (c) wet granulating atazanavir bisulfate and drying the wetgranulation to form Pattern C material; or (d) mixing Form A crystalswith one or more formulating excipients and wet granulating theresulting mixture to directly form Pattern C material in admixture withthe excipients.
 25. A process for preparing atazanavir bisulfate

in the form of Form A crystals, which comprises preparing a triaminesalt of the structure

and without isolating the triamine salt, reacting the triamine salt withan active ester of an acid of the structure

and a base in the presence of an organic solvent to form a solution ofthe atazanavir free base of the structure

and converting the free base to the corresponding bisulfate salt. 26.The process as defined in claim 25 where the triamine salt is thehydrochloride salt


27. The process as defined in claim 25 wherein the active ester of theacid has the structure


28. The process as defined in claim 25 wherein the base is an alkalimetal hydroxide, an alkaline earth metal hydroxide, an alkali metalcarbonate, an alkaline earth metal carbonate, an alkali metal phosphate,an alkaline earth metal phosphate or an organic base.
 29. The process,as defined in claim 27 wherein the base is NaOH, KOH, Mg(OH)₂, K₂HPO₄,MgCO₃, Na₂CO₃, K₂CO₃, triethylamine, diisopropylethylamine orN-methylmorpholine and the organic solvent is methylene chloride, ethylacetate, dichloroethane, tetrahydrofuran, acetonitrile orN,N-dimethylformamide.
 30. The process as defined in claim 25 whereinthe triamine salt and the active ester are reacted at a temperaturewithin the range from about 30 to about 40° C.
 31. The process asdefined in claim 30 wherein the triamine salt and the active ester arereacted in the presence of K₂HPO₄ as the base and methylene chloride asthe solvent.
 32. The process as defined in claim 25 wherein the freebase is converted to the corresponding bisulfate salt by treating asolution of free base in methylene chloride with N-methylpyrrolidone andacetone, heating the above mixture to remove methylene chloride andtreating the above mixture with sulfuric acid to form the bisulfate saltof the free base.
 33. The process as defined in claim 32 including thestep of seeding the mixture of free base, acetone andN-methylpyrrolidone with crystals of atazanavir bisulfate.
 34. Theprocess as defined in claim 25 wherein the sulfuric acid is added at anincreasing rate according to the following equation$V_{time} = {V_{total} \times ( \frac{time}{{time}_{total}} )^{3}}$where V_(time)=Volume of sulfuric acid added during elapsed time periodV_(total)=Total volume of acid representing the 90% charge time=Elapsedtime in crystallization time_(total)=Total crystallization time or totaltime for acid charging
 35. A process for preparing atazanavir bisulfate

which comprises preparing a triamine hydrogen chloride salt of thestructure

reacting the triamine hydrogen chloride salt with an active ester ofstructure

and K₂HPO₄ in the presence of methylene chloride to form a solution ofthe free base of the structure

in methylene chloride, and converting the free base to the correspondingbisulfate salt via a cubic crystallization technique.
 36. Apharmaceutical formulation comprising atazanavir bisulfate Pattern Cmaterial as defined in claim 9 and a pharmaceutically acceptable carriertherefor.
 37. The formulation as defined in claim 36 comprisingatazanavir bisulfate Pattern C material, one or more fillers, one ormore disintegrants, optionally one or more binders, and optionally oneor more glidants or lubricants.
 38. The formulation as defined in claim36 comprising atazanavir bisulfate Pattern C material, lactose,crospovidone, and magnesium stearate.
 39. A pharmaceutical formulationcomprising Form E3 of atazanavir bisulfate as defined in claim 16 orForm A of atazanavir bisulfate and a pharmaceutical acceptable carriertherefor.
 40. A method of treating diseases caused by retroviruses,which comprises administering to a human patient in need of treatment atherapeutically effective amount of atazanavir bisulfate Pattern Cmaterial as defined in claim 9 or Form A or Form E3.